Lighting or surge arresters are typically connected to power lines to carry electrical surge currents to ground, and thus, prevent damage to lines and equipment connected to the arresters. Arresters offer high resistance to normal voltage across power lines but offer very low resistance to surge currents produced by sudden high voltage conditions caused, for example, by lighting strikes, switching surge currents or temporary overvoltages. After the surge, the voltage will drop and the arrester should normally return to a high resistance state. However, upon arrester malfunction or failure, the high resistance state is not resumed, and the arrester continues to provide an electrical path from the power line to ground. Ultimately, the line will fail due to a short circuit condition or breakdown of the distribution transformers, and the arrester will require replacement.
To avoid line failure, disconnectors are commonly used in conjunction with arresters to separate a malfunctioning arrester from the circuit and provide a visual indication of arrester failure. Conventional disconnectors have an explosive charge to destroy the circuit path and physically separate the electrical terminals. Examples of such prior disconnector devices are disclosed in U.S. Pat. Nos. 5,057,810 and 5,113,167 to Raudabaugh, as well as U.S. Pat. No. 5,434,550 to Putt and U.S. Pat. No. 4,471,402 to Cunningham, the subject matter of each of which is hereby incorporated by reference.
However, these conventional disconnector devices comprise a relatively large number of intricate parts which are relatively expensive to manufacture and assemble. Additionally, their configurations have relatively high reaction times for detonation due to the limited exposure of the cartridge.